global.gc();
console.log(process.memoryUsage());

const wm = new WeakMap();
let key = new Array(100000000);
wm.set(key, 1);
global.gc();
console.log(process.memoryUsage());

key = null;
global.gc();
console.log(process.memoryUsage());

for (let [k, v] of wm.entries()) {
    console.log(k, v);
}
